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以余庆-凯里高速公路12标土样为研究对象,采用三轴试验研究了两种干湿循环方式(先干后湿和先湿后干)对压实红黏土抗剪强度指标的变化规律,并对干湿循环下边坡稳定性计算参数进行了探讨。研究结果表明,干湿循环作用显著降低了压实红黏土的抗剪强度指标,其中第一次衰减幅度很大,但经过一定次数的干湿循环作用后,强度指标趋于稳定状态。干湿循环对压实红黏土黏聚力的影响比内摩擦角影响要大。不同的干湿循环路径对压实红黏土抗剪强度指标影响的规律基本一致,但是先湿后干条件下压实红黏土抗剪强度指标比先干后湿要大。干湿循环下边坡稳定性计算参数取值建议采用长期强度指标值,黏聚力稳定值未经循环值的45%~55%,内摩擦角稳定值为未经循环值的45%~65%。研究结果更好地为红黏土地区工程建设提供技术依据。
Taking 12 samples of Yuqing-Kaili Expressway as samples, the changes of shear strength index of compacted red clay were studied by three-axis test with two kinds of wet-dry cycles (dry first and then wet first) Regularity, and the parameters of slope stability under wet-dry cycle are discussed. The results show that the wetting and drying cycles significantly reduce the shear strength of compacted red clay, of which the first decay rate is large, but after a certain number of wet-dry cycles, the strength index tends to be stable. The influence of the wetting and drying cycle on the cohesion of compacted red clay is greater than that of the internal friction angle. The laws of the influence of different wet-dry circulation paths on the shear strength index of compacted red clay are basically the same, but the shear strength index of compacted red clay is higher than that of the first dry wet clay. The value of long-term strength index is recommended for the calculation of slope stability parameters under dry-wet cycle. The stability of cohesion value is 45% -55% of the uncycled value, and the stable value of internal friction angle is 45% -65% of uncycled value. . The results of this study will provide better technical basis for engineering construction in red clay area.